The Usages combined fragments of Roman and Visigothic law with the resolutions of the comital court of Barcelona and the religious canons of ecclesiastic synods. The first Usages were compiled and codified by Ramon Berenguer I, Count of Barcelona (1035–1076), to repair the deficiencies of Gothic law. However, the evidence for Ramon's work dates from the codes of James the Conqueror of a later date (reigned 1213–1276). James, seeing that some judges ruled by Gothic law and some by Roman law, according to a tradition of usus terrae (local custom), approached the Corts in 1251 to establish the primacy of the Usages. Though the Usages applied legally only to the Barcelonan county, in practice they were applied to the entire Principality of Catalonia.

The Usages incorporated several other competing codes of the same era:

The oldest manuscript containing the Usages dates from the end of the 12th century. Between the 15th and 18th centuries, they were copied frequently. The Nueva Planta decrees superseded them with the central legislation of the Bourbons, though continued to have some force.